If you're used to working with 'flags' or 'bits' then this stuff should look familiar to you. If it looks like Greek, a bit of an explanation about 'hexadecimal numbers' and 'bitwise operators' might be useful... have a read of our article on flags'n'stuff.

This part simply catches a command that a player enters on the console (type "\rbounce", for example) and calls the function Cmd_RBounce_f(). We like to think of this part of code as our 'hook' to the outside world :)

The if (self->flags & FL_ROCKETBOUNCE) bit tests if the particular client has FL_ROCKETBOUNCE turned on. If so, the rocket will explode after 2.5 seconds (instead of 10). The magic part is adding EF_BOUNCE to the rocket's eFlags (which I suppose stands for 'effects flags'... browse bg_public.h line 195 for a list of all the EF_ flags).